Presentation
Postoperative pain and functional shoulder limitation on abduction.
Patient Data
Postoperative control (supine)
Humeral component in high position with normal acromiohumeral interval.
Twelve months control
Humeral component high position with significant reduction in the acromiohumeral interval.
In the axial projection, there is anterior humeral component subluxation.
Compared to the initial tilt, the prosthetic stem is in varus.
Case Discussion
The rotator interval defines the space available for the rotator cuff and is about 10 mm.
In shoulder arthroplasty, care should be taken not to use an oversized humeral head component and to perform glenohumeral capsular releases to accommodate the head (and in total arthroplasty, also glenoid) component, so as to avoid decreased range of motion and stiffness.
The normal distance between the humeral component head and the tuberosity should be 5 mm, higher than that is considered overstuffing.
In joint overstuffing, the tension and traction on the rotator cuff and the capsular ligamentous complex increase with arm elevation.